I have a '87 Sierra 2.8 V6 XR4x4 in which the gearbox decide to give up and only select 4th. Since this happened I've changed it for a MT75 gearbox out of a latter 2.9 car. Everything has bolted up fine with no real hassle. My problem is that when I have tried to fit the starter motor (the one for the MT75 box not my original one) back in it doesn't clear the fins from the sump that go out to the driveshafts. I'm sure this has been done before so could you please tell me what car I need to get a starter motor from?